It is always difficult to find a perfect translation! :) but i would say that it is depending on the context.

they can be the same meaning but sometimes not. 

日本語を知っています。 - I know about Japanese. /  I have heard "Nihongo"  (but i can't speak)

日本語がわかります。 - I know how to speak Japanese /  I understand Japanese

この漢字を知っています。 -  i know about this Kanji / I have seen this kanji (but i don't remember how to read)

この漢字がわかります。- i know how to read this kanji / i know what this kanji means.

かれの名前を知っています。 i know his name./ i have heard his name.

かれの名前がわかります。 i know his name. / i can find his name i understand his name.

I hope it helps.

Hi, 

In Japanese,  "知る" means "know" and, "わかる" means "understand".

So, 知る it is used when you get some information about what.

わかる it is used when you've recognized in yourself something about what. 

I'm glad if my explains could help you.

わかる is always used when you want to say you understand something. 

E.g.: Person- わかる？

　　You: わかった。

However, わかる is also used to say if you know something. It is often used with かどうか and embedded questions, whereas 知る is used for knowing a specific thing, e.g. 彼の名前を知りますか。

Hope this helps!